I have a 390 block with no year marked on it? the webbing on the crank is not reinforced webbing, standard webbing. It has 40 DIF on the block which is Dearborn Iron Foundry but, what is the 40? Also this block has numbers all over the block in key areas eg., crank saddles, block skirt, front\ back of block, lifter gallery, what are these numbers for? Someone told me it had to do with the amount of or strenght of iron used in these areas? How much power will this block handle without the reinforced webbing if much difference? Should I find a Block with the reinforced webbing out of a truck or does it depend on the block I have? Anyone out there can help me?

You will see a date code right below the oil filter adapter pad. It will be a number/letter/number(s) series. Year/month/day. If you can post them I'll decode it and you'll know the casting date of the block. Not all FE blocks have casting numbers and most that do will not tell you the exact displacement or application. The 40 by the DIF is part of the molds numbering system. If a defect was found this allowed the offending mold to be removed for repair or replacement. It had nothing to do with tensile strength of the nodular iron. I have heard tensile strength dropped in the 70's on FE blocks. As a result the HD block casting was used from then on. But haven't seen factory documentation to back up that claim. What kind of HP and TQ are you planning? What bore and stroke? If your planning like 500hp you should be fine with that block.

I am not sure how much you want out of this 390 Build ? I have worked on some FE's and Truck FT's over the Years at Home and on the Job . Have I ever built one that was a Strip only Engine No I have not . I have help rebuild two 428's both were in GT-500's . And I have replaced Heads on a Few 391 FT Truck Engines .

I Have Personally Seen how much abuse them 361's and 391's FT Truck engines can Take . They are Very Tough . I Like the FE's but to be honest to go back to the 70's when I did see Lots of them on the Street and Track . The one's that I watched run really were not that Fast ! Not saying they are bad Engines and I am sure the Performance parts of today can make a world of Difference to them . Back then they really were not at all a threat to most other Performance cars . Now them 385 Type BB Ford's 429SCJ's had some Large Nut's and would rage real good

I fixed am and they run good after . But most were stock rebuilds . I enjoy working on FE's but that intake is Like 1/3 of that Engine It takes Two Men and a Boy to install an Iron Intake on one of them in a Straight Truck

Heck the ones at the Track were built By Die Hard Ford Boys . If one of them ran 13 Teens it was Like a Party in their Pit Ha-

I Still Like them Engines I had my Hands on more of them then you would think

It's going into a 1976 SWB F_100 truck. There is no casting numbers on this block. I just have numbers all over the block in different placec no c-1 -c9 or D-1 -D2. I have another block that has c7 ae something, I know it is a 1967 block but, this one doesn't have any numbers in the right location? I will show you my truck, it will be my avaitar.

You will see a date code right below the oil filter adapter pad. It will be a number/letter/number(s) series. Year/month/day. If you can post them I'll decode it and you'll know the casting date of the block. Not all FE blocks have casting numbers and most that do will not tell you the exact displacement or application. The 40 by the DIF is part of the molds numbering system. If a defect was found this allowed the offending mold to be removed for repair or replacement. It had nothing to do with tensile strength of the nodular iron. I have heard tensile strength dropped in the 70's on FE blocks. As a result the HD block casting was used from then on. But haven't seen factory documentation to back up that claim. What kind of HP and TQ are you planning? What bore and stroke? If your planning like 500hp you should be fine with that block.

.30-.40 over bore and 3.784 stroke with a pair of ported and polished C6 ae-R heads, 11.1 cp with a Street Master intake and a Predator carb mounted on top of it.

It's going into a 1976 SWB F_100 truck. There is no casting numbers on this block. I just have numbers all over the block in different placec no c-1 -c9 or D-1 -D2. I have another block that has c7 ae something, I know it is a 1967 block but, this one doesn't have any numbers in the right location? I will show you my truck, it will be my avaitar.

Do you only have the Block or also have the Crankshaft and Rods ? Check the Bore Size and Main Bearing Block Diameter . I don't think it's going to make a Big Difference when it was casted . Most were all old Engines . And with a Good Set of Rods and a Forged Crankshaft you should be ok with an Under 600 H.P Lower RPM Engine .

So you have 2 blocks to choose from if I reading things right? The C7 and then the other one in question. Unless someone ground it off there's a date code on it. Date code is different from the casting number. If you can post than info or a few pictures of the area it'll help. Or email pics to me if you can post them. The C6AE-R heads are good ones. The last pre smog heads before the changeover in mid 66. 11:1 CR you'll be on the ragged edge on pump gas. Unless you plan using a blend of race gas. Street Master intake is a nice one. Edelbrock has a porting guide for that intake. If it came on the same engine as the C6 heads it might have been done already. Pretty common upgrade.

BTW that's a great looking truck. Very clean. Are those Bullitt rims on it?